The modern-day lifestyle is characterized by a majority of time spent sitting throughout the day. Older people may be especially vulnerable to the harmful effects of prolonged sitting due to a loss of physiologic reserve and the fact that the prevalence of excessive sitting may be especially high in this sector of the population. Metabolic flexibility and glycemic control decline progressively with aging; however, this can be attributed primarily to factors secondary to aging. Indeed, sedentary living is a challenge to metabolic control -especially in older age when insufficient insulin secretion and multi-tissue insulin resistance are also important contributors to impaired glycemic control. Unfortunately, there are few well-controlled human studies testing variations in the degree of metabolic dysregulation resulting from prolonged sitting and whether minimal intensity walking can improve resistance to such dysregulation. The purpose of this proposal is to examine whether low-intensity post-meal walking is an effective counter-measure to prolonged (uninterrupted) sitting for improving glycemic control and metabolic flexibility in older people (=65 y) at risk for type 2 diabetes due o impaired fasting glucose (IFG). Specific aims are: 1) to determine the continuous kinetics of 24h glycemic control under separate conditions of prolonged sitting or intermittent, low-intensity post-meal walking in inactive older people (N=45) with IFG; 2) to determine the enduring effects of a 16-week home-based program of low- intensity post-meal (PM) walking (3x15 min/day performed 1/2 h after each meal on 5 days/week; n=15) vs. intermittent (INT) walking (3x15 min performed 1h before each meal on 5 days/week; n=15) vs. 45 min of sustained (SUS)walking (performed between 9 and 10:30 AM on 5 days/week; n=15) on several biomarkers of insulin sensitivity, glycemic control and lipid metabolism in this same study sample; and 3) to determine whether 16 weeks of lower-intensity training improves resistance to metabolic dysregulation with prolonged sitting. If successful, this strategy would have substantial geriatric relevance - especially since it can be utilized by more frail segments of the older adult population. Given the prominence of the sedentary lifestyle and the excess disease burden associated with disuse and hyperglycemia in older age, there are enormous public health benefits to designing countermeasures that are enjoyable and effective within the populations needing them the most.